Merge pull request #24 from aksio-insurtech:feature/type-serializer

Adding a Type serializer

Samples/Bar.cs

@@ -1,3 +1,3 @@
 namespace Samples;
 
-public record Bar(string Something);
+public record Bar(string Something, Type Type);

Samples/Program.cs

@@ -25,13 +25,13 @@
 db.DropCollection("blahs");
 var collection = db.GetCollection<Blah>();
 
-var b = new Blah("Hello", 42, new Bar("aasd"));
+var b = new Blah("Hello", 42, new Bar("aasd", typeof(string)));
 var doc = b.ToBsonDocument();
 
 // collection.InsertOne(new Blah("Hello", 42, "Something"));
-collection.InsertOne(new Blah("Hello", 42, new Bar("aasd")));
+collection.InsertOne(new Blah("Hello", 42, new Bar("aasd", typeof(string))));
 collection.InsertOne(new Blah("Hello", 42, new Foo("Cat", "Horse", "Bar")));
-collection.InsertOne(new Blah("Hello", 42, new Foo("Cat", "Horse", new Bar("Something"))));
+collection.InsertOne(new Blah("Hello", 42, new Foo("Cat", "Horse", new Bar("Something", typeof(string)))));
 
 
 // var items = collection.Find(_ => true).ToList();

Source/CustomObjectDiscriminatorConvention.cs

@@ -49,6 +49,5 @@ public Type GetActualType(IBsonReader bsonReader, Type nominalType)
     }
 
     /// <inheritdoc/>
-    public BsonValue GetDiscriminator(Type nominalType, Type actualType) =>
-        $"{actualType.FullName}, {actualType.Assembly.GetName().Name}";
+    public BsonValue GetDiscriminator(Type nominalType, Type actualType) => actualType.GetTypeString();
 }

Source/MongoDBDefaults.cs

@@ -53,6 +53,8 @@ public static void Initialize(IMongoDBArtifacts? mongoDBArtifacts = default, IDe
                 .RegisterSerializer(new DateOnlySerializer());
             BsonSerializer
                 .RegisterSerializer(new TimeOnlySerializer());
+            BsonSerializer
+                .RegisterSerializer(new TypeSerializer());
 
 #pragma warning disable CS0618
 

Source/TypeExtensions.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Aksio Insurtech. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Aksio.MongoDB;
+
+/// <summary>
+/// Extension methods for <see cref="Type"/>.
+/// </summary>
+public static class TypeExtensions
+{
+    /// <summary>
+    /// Get the type string for a <see cref="Type"/>.
+    /// </summary>
+    /// <param name="type">Type to get from.</param>
+    /// <returns>A type string.</returns>
+    public static string GetTypeString(this Type type) =>
+        (type.Namespace?.StartsWith("System") ?? false) ?
+            (type.FullName ?? type.Name) :
+            $"{type.FullName ?? type.Name}, {type.Assembly.GetName().Name}";
+}

Source/TypeSerializer.cs

@@ -0,0 +1,34 @@
+// Copyright (c) Aksio Insurtech. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using MongoDB.Bson;
+using MongoDB.Bson.Serialization;
+using MongoDB.Bson.Serialization.Serializers;
+
+namespace Aksio.MongoDB;
+
+/// <summary>
+/// Represents a serializer for <see cref="Type"/>.
+/// </summary>
+public class TypeSerializer : SerializerBase<Type>
+{
+    /// <inheritdoc/>
+    public override Type Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
+    {
+        var bsonType = context.Reader.GetCurrentBsonType();
+        switch (bsonType)
+        {
+            case BsonType.String:
+                return Type.GetType(context.Reader.ReadString()) ?? throw new InvalidOperationException("Could not deserialize type.");
+
+            default:
+                throw new NotSupportedException($"Cannot deserialize a {bsonType} to a {nameof(Type)}.");
+        }
+    }
+
+    /// <inheritdoc/>
+    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, Type value)
+    {
+        context.Writer.WriteString(value.GetTypeString());
+    }
+}